It is of growing global concern not only to conserve energy but also to mitigate loss of energy. One such example is with loss of energy in residential or commercial buildings.
There are many known approaches in use today to attempt to address this problem of mitigating energy loss. It is known to use sealants, duct mastic and caulking for sealing around the joints of a heating, ventilation and air conditioner (HVAC) unit. Common sealants include butyl, polyurethane and acrylic sealants. In the case of a sealant, the sealant is typically applied by painting the joint or crack around the heating, ventilation, and air conditioning unit, particularly around joints or seams at the plenum, trunk registers or other duct branches. The sealant is subsequently cured after being applied. Among the disadvantages with such sealants and mastics, for example, are that they are often cumbersome and messy to apply and, once applied, are typically not readily removable or adjustable.
There are also known disadvantages associated with duct tape. It is often advised not to use duct tape in HVAC applications. According to the International Energy Conservation Code published by the International Code Council in IECC 2003 803.2.8 for Duct and Plenum Insulation and Sealing: “All joints, longitudinal and transverse seams, and connections in ductwork, shall be securely fastened and sealed with welds, gaskets, mastics (adhesives), mastic-plus-embedded fabric systems, or tapes. Tapes and mastics used to seal ductwork shall be listed and labeled in accordance with UL 181A or UL 181B. Duct connections to flanges of air distribution equipment shall be sealed and mechanically fastened . . . duct tape is not permitted as a sealant on any metal ducts.” For example, over time conventional duct tape cracks and results in leaks in the system. This creates problems as the joints or seams in a HVAC unit are often inaccessible after installation.
There are also known disadvantages associated with flat HVAC rated aluminum tapes. Such flat aluminum tapes when applied around a circular vent or air duct, for example, leave gaps through which energy can escape. These tapes are often time consuming to apply to minimize gaps around contoured surfaces. Furthermore, they are not easily pliable around such surfaces and readily tear.
Since most duct leakage occurs at the connection to registers, plenums or branches in the duct system, at each of these connections a method of sealing the duct system is required. Field examination of duct systems have typically shown that these seals tend to fail over extended periods of time. ASTM Test Method E 2342-03, which is the standard test method for “Durability Testing of Duct Sealants,” evaluates the durability of duct sealants by blowing heated air into test sections, combined with a pressure difference between the test sections and their surroundings. In the Method E 2342-03, the temperatures and pressures were chosen to expose the test sections to typical conditions that are found in residential duct systems. The duct leakage site geometry represents a leakage site commonly found in duct systems. Therefore, there is a need for a more efficient and reliable method to seal joints, and hence mitigate energy loss, in a HVAC unit, particularly in the plenum, trunk registers or other duct branches of a HVAC unit.